Searching for Evidence of Extension on Mercury

Of Interest: Mercury's surface shows many lobate scarps, which are caused by contraction (horizontal shortening) of the crust. In contrast, surface features indicative of extension (horizontal stretching) are rare on Mercury and have been previously identified only within the interiors of four large impacts basins: Caloris basin, Raditladi basin, Rembrandt basin, and a newly imaged basin from Mercury flyby 3. However, MESSENGER's high-resolution images are enabling an examination of Mercury's surface in unprecedented detail, and the above image shows the first evidence of extension outside of the floor of an impact basin. Visible near the center of the image are two narrow, northeast-southwest-trending troughs (orange arrows), interpreted to be landforms created by faulting in response to crustal extension. MESSENGER Science Team members are presenting these new results today at the annual Lunar and Planetary Science Conference held near Houston, Texas. In total, 20 MESSENGER papers are being presented at this conference to members of the planetary science community.